The invention relates to an image generation device having an array of image-forming elements, as well as to a method for producing such an array of image-forming elements.
On account of their structure in comparison with conventional single-channel projectors, micro-optical array projectors enable sharp images with a low light loss. As described in DE 10 2009 024 894 A1 for example, such an array projector has a regular arrangement of projecting individual channels, the projections of which are combined on the screen to form the overall image. The ultra-flat array projection display presents an innovative optical concept for implementing flat and simultaneously bright projection systems.
The basic principle is schematically illustrated in FIG. 1. A light source 1 illuminates a field lens array 2, in the immediate vicinity of which the array of image-forming structures 3 is situated. The object to be projected is situated in the focal length of the associated lens of the projection lens array 4. In comparison with the distance between the projection lens and the object, the corresponding field lens is very close to the object in order to ensure Köhler illumination of the projection lens. The projection lens array images superimposition of all individual images onto a screen 5.
A further development of this technology makes it possible to generate images to be projected at different projection distances. Such a system is described, for example, in DE 10 2013 208 625 A1. The images are generated statically, that is to say there is no need for any conversion either at the imager or mechanically. For this purpose, the individual images of the multi-channel projection display must be suitably created. This is carried out by means of a Boolean combination of the individual images for the projection channels of the multi-aperture display. The information relating to the image-forming elements is combined, projection channel by projection channel, to form the definitive individual images at least two different projection distances L1 and L2 by means of the light source. The principle is schematically shown in FIG. 2.
In order to project the images into the different planes, special generation of the individual images is selected. For each projection which is intended to be generated, the individual image of the image-forming elements is first of all calculated, those of the two projections 5 and 6 in the example shown. The back-projection into the object planes of the optics is illustrated in FIG. 3. The back-projection of one image is illustrated by the hatched “F” (reference symbol 7). The back-projection of the second image is illustrated by the opposite hatching 8. In this case, the outer surfaces image the image at the shorter projection distance. The superimposition 10 of both types of hatching and therefore also the superimposition of the two back-projections can be clearly seen in FIG. 3.
This is a logical “AND combination”. The individual types of hatching are an illustration which is not used in the optical system. FIG. 4 illustrates the mask array with the transmissive surfaces 10. In this case, the region in which the surfaces are superimposed is described as transmissive surfaces since they transmit the light during use. It can clearly be seen that only those surfaces on the mask array which have been created by means of the “AND combination” in FIG. 3 are transmissive. The superimposition of the transmitted light through the image-forming elements produces the images in the various projection planes. This embodiment is also possible with different images. A different image, for example the letter “A”, to that displayed on the long projection path, for example the letter “B”, can therefore be displayed on the short projection path. In this case, the same optical system and the same way of combining the image-forming elements are used.
The disadvantages of the multi-channel projection displays known from the prior art are the currently very high demands imposed on the lateral adjustment of the projection lens array with respect to the array of the image-forming elements during the production process. Furthermore, the multi-channel projection displays known from the prior art have a high degree of sensitivity during use, in particular with respect to vibrations, shocks and the like.
An object of at least some embodiments is to provide an image generation device which has increased tolerance with respect to misalignments between an array of image-forming elements and a projection lens array. Another object is to provide a method for producing an array of image-forming elements.
These objects are achieved by an image generating device and a method for producing image-forming elements according to embodiments of the invention.
An image generation device according to the invention has at least one light source, a field lens array, an array of image-forming elements and a projection lens array. In this case, the field lens array comprises a plurality of field lenses, the array of image-forming elements comprises a plurality of image-forming elements and the projection lens array comprises a plurality of projection lenses.
An image-forming element is preferably assigned to each field lens and a projection lens is preferably assigned to each image-forming element. The image generation device may be in the form of a micro-optical array projector, a multi-channel projection display or a multi-aperture projection display, for example. The image-forming elements preferably each have a projection pattern. The image-forming elements or the projection patterns may be formed by transmissive surfaces, for example. The image-forming elements are therefore shadow masks which can be back-lit, for example. Furthermore, the image-forming elements may also be, for example, self-luminous elements, for example OLEDs or displays.
The array of image-forming elements is preferably formed by superimposing a first pattern array and a second pattern array, the second pattern array being rotated with respect to the first pattern array. The individual image-forming elements in the array formed by the superimposition may each be different.
The first pattern array and the second pattern array are preferably each pattern arrays of image-forming elements, that is to say the first pattern array and the second pattern array each preferably have a multiplicity of image-forming elements which may be in the form of projection patterns or transmissive surfaces, for example. The first pattern array and the second pattern array are preferably structurally identical. For example, the first pattern array and the second pattern array may have an identical structure with regard to their image-forming elements, for example with respect to the number, arrangement, shape and size of the image-forming elements. It is also preferred for the individual image-forming elements or projection patterns to each be identical within the respective pattern arrays.
In the image generation device described here, the geometrical component requirements are advantageously relaxed in comparison with rotated and/or shifted positions of the projection lens array with respect to the array of the image-forming elements.
The pattern arrays need not be real or concrete arrays of image-forming elements; rather, it suffices to simulate a superimposition of at least two pattern arrays for the purpose of forming the array of image-forming elements in order to obtain the image-forming elements in the array of image-forming elements of the image generation device described here. The pattern arrays may therefore be imaginary pattern arrays. The pattern arrays which are superimposed on one another are preferably each arranged in the same plane.
The image-forming elements in the array of image-forming elements may be formed, in particular, by superimposing the image-forming elements in the first pattern array and the image-forming elements in the second pattern array. The superimposition may be formed, for example, by means of a logical AND combination. For example, the logical AND combination is formed by the intersection of the image-forming elements in the first pattern array and the image-forming elements in the second pattern array or of the respective projection patterns or transmissive surfaces.
According to another embodiment, the second pattern array is rotated with respect to the first pattern array with regard to an axis of rotation which is perpendicular to the first pattern array. In particular, the axis of rotation may be arranged perpendicular to a plane in which the image-forming elements in the first pattern array are arranged. For example, the axis of rotation may run through the first pattern array. Alternatively, the axis of rotation may also run outside the first pattern array, that is to say there is no point of intersection between the axis of rotation and the first pattern array.
According to another embodiment, the second pattern array is rotated with respect to the first pattern array through a predefined angle of rotation, the angle of rotation being between 0.005° and 2.0°, preferably between 0.005° and 1.0°. According to a particularly preferred embodiment, the angle of rotation is between 0.1° and 0.5°.
According to another embodiment, the second pattern array is additionally shifted with respect to the first pattern array. In particular, the individual image-forming elements or projection patterns of the second pattern array may each be shifted by the same distance or translation path with respect to the associated image-forming elements or projection patterns of the first pattern array. In contrast to this, the various second back-projections 8 from FIG. 3 are each shifted by different translation paths with respect to the various first back-projections 7.
According to another embodiment, the array of image-forming elements is formed by superimposing three pattern arrays. In particular, the array of image-forming elements can be formed by superimposing a first, a second and a third pattern array, the three pattern arrays each being structurally identical. The three pattern arrays may each have, for example, a plurality of image-forming elements and may have an identical structure with respect to the image-forming elements, in particular with regard to the number, size, shape and arrangement of the image-forming elements. The image-forming elements in the array of image-forming elements of the image generation device described here may be formed by superimposing the image-forming elements in the three pattern arrays. The superimposition may be formed, for example, by means of a logical AND combination. For example, the logical AND combination is formed by the intersection of the image-forming elements in the first pattern array, the image-forming elements in the second pattern array and the image-forming elements in the third pattern array or of the respective projection patterns or transmissive surfaces. In this case, the pattern arrays need not be real or concrete arrays of image-forming elements; rather, the superimposition of pattern arrays can be simulated in order to form the array of image-forming elements of the image generation device described here.
According to another embodiment, the second pattern array is rotated with respect to the first pattern array through an angle of rotation of between 0.005° and 1.0°, and the third pattern array is rotated with respect to the first pattern array through an angle of rotation of between −0.005° and −1.0°. The angles of rotation between the second and first pattern arrays and between the third and first pattern arrays are particularly preferably of the same magnitude.
An array of image-forming elements is also provided. The array of image-forming elements may have one or more features of the embodiments mentioned in connection with the array of image-forming elements of the image generation device. In particular, the array of image-forming elements is formed by superimposing a first pattern array and a second pattern array, the second pattern array being rotated with respect to the first pattern array and the first and second pattern arrays being structurally identical.
A method for producing an array of image-forming elements is also provided. The array of image-forming elements which can be or is produced thereby may have one or more features of the above-mentioned embodiments.
In the method, an array of image-forming elements is formed by superimposing a first pattern array and a second pattern array which is rotated with respect to the first pattern array. The first pattern array and the second pattern array are preferably structurally identical. The pattern arrays may each have a multiplicity of image-forming elements and may have an identical design with respect to the image-forming elements.
According to another embodiment, the image-forming elements in the array of image-forming elements of the image generation device described here are formed by superimposing the image-forming elements in the second pattern array and the image-forming elements in the first pattern array. The superimposition is preferably formed by means of a logical AND combination. For example, the logical AND combination is formed by an intersection of the image-forming elements or the projection patterns or transmissive surfaces of the pattern arrays.
The first pattern array and the second pattern array or the image-forming elements in the pattern arrays can be superimposed by means of a simulation, for example. Therefore, the pattern arrays and their image-forming elements need not be present as concrete pattern arrays; rather, the array of image-forming elements of the image generation device described here can be formed by means of the simulation.
According to another embodiment, the second pattern array is rotated with respect to the first pattern array through a predefined angle of rotation of between 0.005° and 1.0°. In addition, the second pattern array may also be shifted by a predefined translation path with respect to the first pattern array.
According to another embodiment, three pattern arrays which are each rotated with respect to one another are superimposed in order to form the array of image-forming elements. For example, the image-forming elements in the array of image-forming elements can be formed by superimposing the image-forming elements in the three pattern arrays.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of one or more preferred embodiments when considered in conjunction with the accompanying drawings.